Process for production of transparent effects in cotton fabrics



that transparent Patented June 16, 1925.

UNITED STATES;

* 1,542,202 PATENT OFFICE.

ROBERT, ZIMMERMANN, OF TUBACH, SWITZERLAND, ASSIGNOR TO THE FIRM TEX- TILWERK HORN A.G., OF HORN-ON-THE-BODENSEE, SWITZERLAND.

PROCESS FOR PRODUCTION OF TRANSPARENT EFFECTS IN COTTON FABRICS.

N'o Drawing.

To all whom it may concern:

Be it known that 1, ROBERT ZIMMERMANN, a citizen of the Republic of Switzerland, residing at Tubach, Canton St. Gall, Switzerland, have invented certain new and useful Improvements in. a Process 'for Production of Transparent Effects in Cotton Fabrics. of which the following is a specification.

As is well-known, the treatment of cotton fabrics with sulphuric acid over 50 B. containing water, produces a transparent effect, but at the same time renders the fabric unpleasantly stiff.

lt has been new found that the drawback in question may be obviated by using sulphuric acid which, in addition to water, contains also ammonia salts in solution. Such solutions contain acid ammoniunrsulphate (NIL)HSO,. and they may replace part of the water of the usual sulphuric acid of with the technical effect fabrics are produced which are soft to the touch. After treatment with such acid-ammonium salt-water solution, the fabric has a characteristic soapy slimy touch. On the washed fabric being dried, it becoi'nes as soft as velvet and on being moistened, again becomes soapy.

As suitable solutions may be mentioned for instance those containing 69% sulphuric acid, 5% ammonium sulphate and 26% water, or 72% sulphuric acid, ammonium sulphate dissolved as such, and 18% water, or 82% sulphuric acid, 12% ammouium sulphate dissolved as such and 6% water. Further, many other variations in the pro 'iortions are possible.

It must be pointed out that the greater the proportion of ammonium sulphate in the solution, and the smaller the proportion of water, the softer will be the transparent fabric produced. For rendering the fabric transparent with one of the above solutions, the treatment should be carried out at temperatures of 1048 and the tinle of reaction should be 510 seconds. But the treatment may also be carried out. at lower temperatures and longer periods.

Instead of dissolving ammonium sulphate in sulphuric acid containing the correct proportion of water, it is possible also-bearing in mind. the formation of water to introduce into the sulphuric acid hartshorn salt (NHJHCO and after its decomposition, to allow the hot solution to cool. Solutions -54 degrees,

Application filed March 28, 1923. Serial No. 628,324.

suitable for rendering fabrics transparent may also be produced with sal ammoniac, ammonium acetate and phosphate. thus be seen that ammonium salts may be added to the sulphuric acid bath whose de composition products remain in solution in the bath and which formfwith sulphuric acid, sulphates that reduceor modulate the hardening action of the sulphuric acid on the fibre of the goods.

It will be noted from the examples given that the strength of the acid bath in acid content may increase with an increase in the percentage of ammonium sulphate present in the bath.-

For the purpose of .obtaining soft transparent fabrics, it is preferable toaise well bleached niercerized fabric which has been dried in a state of tension. Or the transparent effect may be still further increased by subsequent mercerizing with soda lye of different concentrations, for instance 28 Be, washing and drying in a state of tension. The fabric may be repeatedly submitted to treatment to render it more transparent and softer, then, washed and dried in a state of tension.

Pattern effects may be produced b applyingresisting substances such as ru her solution, glue, etc. and drying before submitting the fabric to treatment rendering it transparent and soft.

I claim:

1. Process of treating cotton fabrics to produce transparent effects and to produce fabrics that are soft to the touch, which comprises treating the fabric with a sulphuric acid bath containing an ammonium sulphate soluble in said bath, the quantity of sulphuric acid being greater the greater the quantity of soluble sulphate present.

2. Process of producing cotton fabrics softto touch and having" a transparent effect which process comprises subjecting the fabric to a treatment with a bath containing sulphuric acid, water and at least 5% ammonium sulphate in solution.

'3. Process of producing cotton fabrics soft to touch and having a transparent effect which process comprises'subjecting the fabric to a treatment with an acid-ammonium-salt-water solution consisting of 69- 82% sulphuric acid, 266% water, 542% ammonium sulphate.

4. Process for producing cotton fabrics It will soft to touch and having a transparent effect which ,process comprises mercerizing the bleached fabric drying the mercerized fabric in a state of tension, and subjecting the fabric to a treatment with a bath of sulphuric acid, water and not less than 5% of an ammonium salt in solution.

*5. Process for producing cotton fabric soft to touch and having a transparent effect which process comprises subjecting the fabric to a treatment with sulphuric acid, water and at least 5% of an ammonium salt in solution, mercerizing the treated fabric, washing and drying the fabric in a state of tension.

6. Process of producing cotton fabric soft to touch and having a transparent effect which process comprises repeatedly subjecting the fabric to a treatment with a bath containing sulphuric acid, water and at least 5% of an ammonium salt in solution with intervening merc'erization.

7. Process of producing soft, pliable cotton fabrics having a transparent effect,

a bath containing which comprises treating the fabric with a bath containing at least 69% of sulphuric acid, water, and at least 5% of ammonium sulphate, the percentage of acid being higher the higher the percentage of ammonium sulphate.

8. Process of producing soft, pliable cotton fabrics having transparent effect, which comprises treating the fabric with a bath containing sulphuric acid and water, to which has been added an ammonium salt- ROBERT ZIMMERMANN.

ammonium sulphates. 

